For airtight stove appliances used for heating applications, the combustion cycle is controlled by the amount of air flowing into the stoves. The air is required to complete the combustion cycle with a fuel source, with the combustion cycle also influenced by the specific design of the firebox, the type of fuel, and the exhaust system. A basic firebox comprises an airtight box with a door for loading fuel, a manually-operated draft control arrangement to control the pilot, primary, secondary and any other air intakes for combustion, and a flue system for exhaust in order to maximize efficiency and optimize bum time. The draft control arrangement comprises a draft plate covering the opening for the pilot, primary and secondary intakes, and operates by manually pushing and pulling a control lever connected to the draft plate to control the amount of an air opening for the air intakes.
With reference to FIG. 1, a conventional draft control arrangement 100 may comprise a draft box 102 having an air opening 112 configured to allow air intake into a firebox. Air opening 112 is covered by a draft plate 104, the movement of which is controlled by pushing or pulling on a manual control lever 106 to adjust the amount of air intake into the firebox. A mechanical linking system 118 such as a co-axial cable is used to connect manual control lever 106 to draft plate 104.
Such conventional manually-operated draft control arrangements have various drawbacks. For example, if a single plate is used to control all of the air intake openings, due to a linear relationship between the amount of air opening 112 against the supplied air to the firebox via the pilot, primary and secondary intakes, the performance of the stove appliance is limited. In addition, if multiple plates are used for each air intake, the combination and complexity of such a control lever system is not feasible for manual operation, and far too complex for any user to operate. Further, it is impossible to develop a control relationship based on the performance of the stove in terms of burn time, heating capacity and thermostatic control.